condensation | AiDomes

 Ventilation Systems

The following came from their web site:  

http://energystar.gov/ia/new_homes/features/SupplyVent1-17-01.pdf 

The air within homes can become stale from moisture, odors, and pollutants that penetrate the home or are generated internally by human activity and out gassing from building materials and furnishings.  A constant supply of fresh, outdoor air can provide greater assurance of good indoor air quality and improved comfort. 

In most homes, ventilation is provided accidentally when air leaks through the building envelope.  Accidental ventilation is unreliable because it is dependent on a pressure difference between indoor and outdoor spaces caused by temperature or wind variations.  Too much fresh air often enters a house during cold weather, causing uncomfortable drafts and high heating bills.  Not enough fresh air may enter during mild weather which can lead to poor indoor air quality. 

Air leakage through the building envelope accounts for between 25 percent and 40 percent of the energy used for heating and cooling in a typical residence.  Many new homes are being air sealed to reduce this energy use.  Where tighter construction reduces air leakage and accidental ventilation, active ventilation systems may be needed to provide fresh air. 

Figure 1 shows how supply ventilation works in a small home.  Outdoor air enters through a single intake and is distributed through ducts to the living room and bedrooms.  Stale air is removed by leakage throughout the building and through exhaust fans located in the kitchen and bathrooms.  The supply air intake should be located away from sources of pollution, odor or dust—such as the ground, garages, driveways and plumbing or dryer vents.  Supply systems can be turned off when homes are not occupied. 

Fresh outdoor air is provided continuously regardless of weather conditions.  Indoor air quality is improved where fresh outdoor air, low in pollutants, mixes with indoor air, which has become stale from human activity.  Fresh air is provided to the living spaces within a house through properly sized and located vents without causing uncomfortable drafts.  Filters and dehumidifiers can be added to the system near the intake to further remove pollutants and provide humidity control needed in hot, humid climates.  Thus, they can be used safely with all types of heating and cooling equipment. 

Supply ventilation creates positive indoor pressure.  This is advantageous in moderate and hot climates because positive pressure avoids pulling hot, humid air into wall cavities where condensation problems can occur.  In cold climates, positive pressure can possibly lead to moisture problems if hot, moist air is forced into wall cavities where condensation is likely to occur.  In addition, supply ventilation systems avoid “back drafting” combustion gases from appliances and fireplaces into homes.  

Resources for this article: 

The Consumer Guide to Home Energy Savings (Wilson and Morrill), available from the American Council for an Energy Efficient Economy at 510-549-9914

Moisture Control in Homes fact sheet available from the Energy Efficiency and Renewable Energy Clearinghouse (EREC), POBox 3048, Merrifield, VA 22116, (1-800-363-3732)

To read about energy efficiency and the American Ingenuity Dome, view Efficient Ai Dome.

The following information came from:

The United States Environmental Protection Agency’s Energy Star Program’s web site is Energy Star.

Air will leak through a building envelope that is not well sealed. This leakage of air decreases the comfort of a residence by allowing moisture, cold drafts and unwanted noise to enter and may lower indoor air quality by allowing in dust and airborne pollutants. In addition, air leakage accounts for between 25 percent and 40 percent of the energy used for heating and cooling a typical residence.

The amount of air leakage in a house depends on two factors. The first is the number and size of air leakage paths through the building envelope. As shown in Figure 1, these paths include joints between building materials, gaps around doors and windows, and penetrations for piping, wiring, and ducts. The second factor is the difference in air pressure between the inside and outside.

Pressure differences are caused by wind, indoor and outdoor temperature differences (stack effect), chimney and flue exhaust fans, equipment with exhaust fans (dryers, central vacuums) and ventilation fans (bath, kitchen. To prevent air leakage, it is important to seal the building envelope during construction prior to installation of the drywall. Once covered, many air leakage paths cannot be accessed and properly sealed. There are many products available for air sealing including caulks, foams, weather stripping, gaskets and door sweeps.

Air sealing the building envelope is one of the most critical features of an energy efficient home. Look for the results of a “blower door” test (typically included with a Home Energy Rating) to ensure that your Energy Star labeled home had all air leakage paths identified and sealed using appropriate materials.

Once a house is tightly sealed, you will want to make sure there is adequate fresh air for ventilation. It is better to use controlled or active ventilation than to rely on air leakage. In many Energy Star labeled homes, an active ventilation system is installed along with air sealing to ensure that fresh air is provided.

Benefits: air sealing the building envelope can provide many benefits including:

  1. Improved Comfort: A tighter building envelope reduces the amount of unconditioned air, drafts, noise, and moisture that enter your home. Proper air sealing will also minimize temperature differences between rooms. As a result, tight envelopes can maintain a more consistent level of comfort throughout a house.
  2. Improved indoor air quality: A tighter building envelope reduces the infiltration of outdoor air pollutants, dust and radon as well as eliminating paths for insect infestation. Properly sealing the building envelope will also reduce moisture infiltration from outdoor air in humid climates.
  3. Increased quality: Building codes establish the legal minimum construction standards. Energy Star labeled homes, constructed to exceed these codes with air sealing, can offer a better quality product.
  4. Lower Utility Bills: Air leakage accounts for 25 percent to 40 percent of the energy used for heating and cooling and also reduces the effectiveness of other energy-efficiency measures such as increased insulation and high-performance windows. Thus. Air sealing results in lower utility bills.
  5. Fewer condensation problems: Condensation can lead to mold and mildew problems. In hot, humid climates, moisture can enter into wall cavities through exterior cracks and result in costly damage to framing and insulation. In cold climates, gaps in the interior walls allow moisture from warm indoor air to enter wall cavities and attics. This moisture can condense on cold surfaces and lead to structural damage. By significantly reducing air leakage, Energy Star labeled homes can reduce or eliminate these problems.
  6. Reduced obsolescence: Based on recent trends for improved efficiency and higher indoor air quality, tighter building envelopes are expected to become standard practice for the building industry. Since it is both difficult and costly to make the building envelope tighter after a house is constructed, it is best to seal all joints, holes and seams during construction. Energy Star labeled homes constructed to exceed current building codes are therefore, expected to be less vulnerable to obsolescence.
  7. Improved resale position: Air sealing a home can provide the many impressive benefits discussed above and lead to a more comfortable, quieter and better quality home with lower utility bills, fewer condensation problems and reduced obsolescence. These benefits can translate into higher resale value.

Resources used:

    1. The Consumer Guide to Home Energy Savings (Wilson and Morrill), 5th edition, 1996, available from the American Council for an Energy Efficient Economy at 510-549-9914
    2. Homemade Money (Heede and the staff of RMI), 1995, available from the Rocky Mountain Institute at 970-927-3851
    3. Caulking and Weatherstripping fact sheet available from the Energy Efficiency and Renewable Energy Clearinghouse (EREC), POBox 3048, Merrifield, VA 22116, (1-800-363-3732)

The following covers Ai Dome Energy Efficiency FAQS.

EXTERIOR Schoonover

American Ingenuity 40′ dome linked to 30′ garage dome

Q: Where can I view on your web site, the energy bills for your Florida Dome Offices and for a Florida Dome Home?

A: To view the FP&L utility bills showing the Ai 3,700 sq.ft. dome offices can be cooled for less than $85 a month during Florida’s hottest months, view Office Electric Bills. To view the FP&L utility bills showing a Florida 1,075 sq.ft. 34ft in diameter dome can be cooled for less than $27 a month during Florida’s hottest months, view Home Energy Bills.  Heating Ai domes is even easier than cooling because when heating, the heat generated by computers, refrigerators, dishwashers, clothes dryers, etc.  is used and does not need to be overcome as is needed when cooling a structure.

Q: Tell me about an American Ingenuity dome beating a home sponsored by the utility company, Florida Power & Light, to win the award for Most Energy Efficient Residential Unit in the southeastern United States.

A: Florida Power & Light is a nuclear powered utility company in Florida. FP&L sponsored the design of a passive solar home and entered it in a contest held by the Southeast Builder’s Conference, a division of the National Home Builders Association.  An American Ingenuity dome was entered into the same contest.  The Ai dome beat the FP&L home to win the award for the Most Energy Efficient Residence in the southeastern United States. The Home also won the Grand Award for all energy efficient categories…beating out the FP&L home in a second category.

Q: What Energy Star rating has the American Ingenuity dome received?

A: A 5+ Energy Star rating, the highest rating given, Energy Star is a joint program between the Environmental Protection Agency and the United States Department of Energy that is designed to promote products, buildings and homes that use less energy without sacrificing quality.

American Ingenuity has received in the past the Energy Star endorsement for our dome homes, making us the first among Geodesic Domes. Our domes not only qualified but we far exceeded their efficiency standards that are derived from the Model Energy Code.

In an American Ingenuity dome, you can receive a 5+ Star rating, the highest rating given. When financing, this rating will entitle you to the maximum benefits like reduced fees and lower interest rates. The Energy Star Rating cannot be given on a building kit…only on a finished dome. Therefore, once you build your dome you can apply for the Energy Star Rating. Energy Star’s web site ishttp://www.energystar.gov

The Energy Star label can only be placed on completed houses. The label cannot go on a Building Kit. Some of American Ingenuity’s clients have had their completed dome homes rated and received the Energy Star label. To find out how your dome home can receive an Energy Star Label, call the EPA Energy Star hot line 1-888-782-7937 and ask for a company in your area that can rate your home.

Klaus Kolb’s South Carolina Ai concrete dome house earned EPA’s Energy Star.  Home Energy Partners certified his home used 61% less energy than in comparably-size housing.  To view pictures of his dome home, click on Earned Energy Star.  He installed a geothermal cooling & heating system. To view pictures & info about his geothermal system, click on System.  Klaus’s 2003 total monthly average energy bill was $49. This includes the electricity and propane costs for his entire 1,600 sq.ft. – 40 ft. dome.

Q: What do I need to consider when searching for an ENERGY EFFICIENT house?
A:
To best answer that question let us examine how most of the heating and air conditioning is lost in a house. The major loss is usually through the walls and ceiling with the amount of loss directly proportional to the combined area. Solution, minimize the surface area of the house. Domes have about 20% to 40% less surface area than an equal size conventional house. This results in an equal and significant improvement in the efficiency.

The insulation value of the walls and ceilings are important but you cannot just compare R-values. R-values provided for conventional houses represent optimum conditions. They do not take into consideration that the insulation is interrupted by the framing, has voids, settles and absorbs moisture. In our domes, the E.P.S. insulation is continuous, rigid and it will not settle or absorb moisture. R-28 E.P.S. insulation in our dome exceeds the performance of R-45 fiberglass in a conventional house.

Blower tests repeatedly show that wood frame houses loose 10-25% of their heating and AC through the numerous leaks in the walls, attic, electrical outlets, etc. It is very difficult to seal these leaks due to their volume and inaccessibility. American Ingenuity domes are sealed airtight on the outside of the insulation; therefore, eliminating the energy absorbing leaks.

The insulation on Heating and AC ducts is usually only R-6 to R-8. In addition, when the fan is running, the air in the ducts is under pressure and thus the ducts are more inclined to leak. Ducts in the attic, or anywhere outside the insulation envelope, account for sizable energy loss. In American Ingenuity domes all of the ducts are inside the insulation; therefore, there is zero loss in the ducts even if they leak.

If you add up the potential energy savings of American Ingenuity dome living, you will understand why our dome owners often claim savings in excess of 50% to 60%.

To learn more about heating and cooling an American Ingenuity Dome view Energy.

Q: How does your insulation R-value compare to other wall R-values?
A:
The following are comprehensive wall values based on the average value of the complete wall. For example the comprehensive R-value:

  • 2×4 solid wood with 3 1/2″ fiberglass is about R-8
  • Concrete Block, with 3/4″ air, 3/4″ Celotex is about R-9
  • 2×6 Solid wood construction with 5 1/2″ fiberglass is about R-11
  • 2×4 solid wood with 3″ urethane is about R-13
  • While the wall value of Ai’s 7″ thick E.P.S. insulation is R-28 and Ai’s’s 9″thick E.P.S. insulation is R-36.
  • To view data about the modified expanded polystyrene insulation utilized by Ai, click on Panel Composition

Q: How do I remove water vapor from cooking, showering, laundry, etc.?
A:
When the air conditioner or furnace is operating, some water vapor is removed by condensation at the evaporator coil.  Water vapor can be controlled by installing an exhaust fan in top center of the dome, exhaust fans in the bathrooms, at the stove, microwave and clothes dryer. Also if your dome is in a cold climate install a Heat Recovery Ventilator.   To learn more view Heat Recovery Ventilator.

Q: Does thermal mass affect energy efficiency?
A:
No. Generally speaking, in a home, thermal mass is the amount of stuff inside the house that retains heat. Although thermal mass accounts for the fact that some things have a greater “thermal capacity” to store heat than others, to understand its effect you can think of it as the total weight of everything contained in the house.

With more thermal mass (heavy stuff) inside your house more heat will have to be added or removed to change the temperature. Expressed another way, if heat is not being added the temperature will be slower to change.

Does Thermal Mass effect the energy efficiency of the house? No.

As heat in the house is lost through walls, windows, etc. the temperature drops. The thermal mass releases (loans) heat into the house slowing down the temperature change. When the heating system turns on, it must replace heat lost to the outside and it must  replace (pay back) that heat given off by the thermal mass. There is no long-term gain or loss, all of the heat given off by the thermal mass must be replaced. The amount of heat required to maintain the temperature inside a house is solely dependent on the amount of heat that escapes to the outside.

All houses have walls, floors and usually fixtures, appliances and stuff that will retain heat. A large amount of thermal mass can cause long on/off cycles of the heating system when shorter cycles would stir the air more frequently providing more comfort and uniform temperatures inside. The recent generation of thermostats are a proven money saver by lowering the inside temperature (which lowers the heat loss to the outside) during those hours you are away at work, etc. A large thermal mass makes it much harder to change the temperature; therefore, reducing the savings.

During the summer while using AC (substitute cold for heat) the effect remains the same.

Q: Can I use alternative power sources with my American Ingenuity dome?
A:
Yes. By providing your own Alternative Power, you can live in a remote location (less expensive land) and still have all the amenities of a developed area. However be aware the cost of these alternative power sources could be $20,000 to $70,000.  The alternative power systems typically consist of a power source, storage device and conversion systems. Most systems use photovoltaic cells but is some cases gasoline or diesel engine generators or wind or water driven generators are practical. The storage device is usually large batteries. The conversion system allows you to have 110 volts AC and use conventional appliances. The technology is very refined and the systems are top notch.

The cost of the system will depend directly on the amount of power that you will need. By first investing in an energy efficient house, you will reduce your power demand and save money. If you are considering an American Ingenuity dome home, you couldn’t make a better choice and you will be doing your part to conserve power and lower greenhouse emissions.

If you are also connected to the local power grid, you will not need batteries for backup and in most cases you get paid for putting power back into the system.

If the cost of the system is included in the home financing it can be paid off with a little higher monthly mortgage payment. Not having an electric bill may even it out.

Utilizing an alternate power source does have a few drawbacks: COST: while systems are getting more affordable, they are still expensive. It is still less expensive to buy power from mass-produced power companies unless you are far from the power lines. MAINTENANCE and RELIABILITY: Most systems are very reliable but occasionally they need attention. Several of our dome owners have alternative power systems and are very satisfied with the results.

To view pictures and info on a 40′ dome in Pennsylvania which has a GeoThermal WaterFurnace Synergy 3D heating/cooling system, click on Charles Dome.   To info on a South Carolina 40′ dome utilizing geothermal, click on Kolb Dome.  To view pictures of Kolb Dome, click on South Carolina.

Jim Collar’s Utah Ai concrete dome buildings at 7,500 ft elevation operate off the grid by using photovoltaic’s, masonry heater fireplace and passive solar water tubes. To learn more, click on  Off The Grid.   If you are considering an alternative power system in your dome the magazine Home Power offers many solutions. 

 

45' dome with 30' dome in Utah snow.

45′ dome with 30′ dome in Utah at 7,500 ft/ elevation – off the grid. On right are photovotaics

SOLAR HOT WATER PANELS:

Helpful web sites are:

Solar Panels: Solar Hot Water panels can be designed to set on top of the entryways or link. Anchors are buried into the entryway concrete on site. Grooves are cut in the EPS insulation to lay the pipes in and the water pipe(s) are inserted through the entryway EPS before the entryway is concreted. I have a solar hot water panel mounted on my dome link. It sits on the link and lies against the side of the dome. To hide the ends of the solar panel, we filled in the ends with foam and stuccoed over the foam so it matches the dome. View Solar Panels to learn more.

Q: Would you give me more information about solar hot water heaters and photovoltaic panels?
A:
An article in Mother Earth News reported that since 1970, the demand for electricity has outpaced the World’s population growth by more than 20 percent. They continue and explain how we are ignoring the warning signs, that Builders are still constructing poorly efficient housing and others are overlooking the importance of renewable/alternate energy sources.

The first and most important step is to limit or reduce the energy loss in the home. An investment in good, uninterrupted, insulation and a design that does not leak the conditioned air to the outside has the best return. The savings is not only in the reduced energy loss but, also in the reduced cost of a smaller heating and air conditioning system. The next step is to replace some of the energy, which is consumed. A solar water heater has proved to have quick payback in most parts of the country. In fact, sometimes they can be financed and save more money in reduced electric bills than the cost of payments. When they are paid off it becomes pure savings. Photovoltaic cells have continued to improve in efficiency and cost.

The Mathes’ dome (34′ dome home with 30′ garage dome) in Florida utilizes a solar water heater and photovoltaic panels to power their lights and refrigerator. Although, their A/C, washer, well pump and TV are still connected to the meter, their total electric bill was less than $150.00 for the year. The owner/builder states, “This has been a wonderful experience that I would not trade for ANYTHING!”   View Photovoltaic to learn more.

ss2American Ingenuity 34′ dome. Solar Hot water Panel installed on top of standard entryway.

Q: How did the American Ingenuity dome perform in the energy efficiency tests at the Florida Solar Energy Center?
A:
Superbly. Test findings were released after a yearlong study prepared for the U.S. Department of Energy by the Florida Solar Energy Center, a governmental consumer agency, in cooperation with the University of Oregon and the University of Central Florida. This study compared an American Ingenuity dome with an energy efficient, conventionally built structure and a super-efficient Styrofoam house designed by Dow Chemical. It came as no surprise to us that our test dome far surpassed both the conventional and Dow test houses in being THE MOST ENERGY EFFICIENT.

Although the test was conducted in a temperate locale without summer and winter temperature extremes, the American Ingenuity dome outperformed the other structures. In the summer, the energy savings for the dome exceeded 36% and during the winter, the energy savings exceeded 42%. In areas of severe cold and heat, savings would be expected to be considerably higher.

Also, the blower door test showed the dome to be 56% tighter than the conventional test structure and 29% tighter than the Dow house. In tests using infrared, thermal irregularities in the dome were shown to be insignificant.

The Florida Solar Energy Center can be reached at 321-638-1000 or write them at 1679 Clearlake Rd, Cocoa, FL 32922.

Q: Which heating and air-conditioning system is the most practical and efficient for my location?
A:
Keep in mind that because of the superb energy efficiency of the dome the required size of your air conditioning and heating system is reduced to half that of a typical home. It is usually not economical to purchase super-efficient systems because the energy savings is also reduced. The smaller sized domes can be cooled with a window air conditioner. The best heating system will vary with the area and the type of fuel that is readily available. A ventilated wood stove may provide all the needed heat for even our larger domes located to cold climates. A ground water (or water-to-air) heat pump is very efficient for both heat and cool. It uses the constant, moderate temperature of the underground earth to absorb or provide the heat instead of outside air. Besides, being more efficient than an air-to-air unit, it can efficiently produce heat when the outside temperature is below freezing.

Q: Can a radiant in floor heating system be installed in my dome?
A:
Yes. Check your yellow pages or Google local Radiant Floor Heating Subcontractors.

View Radiant Floor Heating to learn more.

Charles exterior

American Ingenuity Dome utilizing radiant floor heating.

Q: Why are your dome homes so energy efficient?
A:
You can save 50-70% on heating and air-conditioning costs with your American Ingenuity dome over a conventionally built home. Some of the reasons for this superb energy efficiency are:

  • Super insulation that does not degrade with time, moisture, or compaction.
  • Spherical shape means reduced exposed surface.
  • Airtight exterior virtually eliminates energy leakage.
  • Solid thermal envelope.
  • Uniform R-value, the insulation is not interrupted with structural members (e.g. 2X4’s roof trusses). The only breaks are the framed exterior walls under entryway and dormer panels that contain your locally purchase exterior doors and windows.
  • Downsized heating and cooling equipment.

Your kit comes with R-28 E.P.S. insulation or if you choose, thicker R-36 E.P.S. insulation is available.

Update your older windows

Windows can add a lot to a home’s character. But if they’re old and worn, they can also add to your heating and cooling bills.

From Better Homes and Gardens.

In older houses, faulty windows can account for a third of the total heat loss in winter and as much as 75 percent of interior heat gain in summer. Look for the following telltale signs that a window has lost its effectiveness:

  • Stand inside your house on a windy day with a lit candle near the window’s operative edge. If the flame flickers or goes out, your weather stripping might be damaged.
  • During the winter, if a window develops ice buildup or a frosty glaze on the interior of the pane, the ventilation in your home may not be adequate. Another possibility is that your window may not be providing enough insulation value, a situation that can make your heating bills soar.
  • If you need to prop open your window with a book or a stick, the window may have lost its functionality.
  • Sit near your window. If you feel cold air coming in during the winter or warm air during the summer, your windows have little insulation value. This means you’re paying more to heat and cool your house to compensate for the exterior air entering your home.
  • Do your windows get fogged with condensation? If so, you may have a seal failure and need to replace the glazing or the entire window.

In some cases, replacing broken panes and tending to loose or missing weather stripping may buy some time. If your windows are old and ill-fitting, however, you need more than stopgaps.

Replacement window options:

Wood is the choice of most homeowners. Wood is strong, insulates well, and has natural appeal and a warm look. It needs exterior maintenance, and interior surfaces can be painted, stained, or finished any number of ways.

Vinyl windows do not need to be painted or stained?a plus on the exterior. They offer good insulation value and strength, making them a viable alternative to wood.

Aluminum windows have a stronger frame but poorer insulation than wood or vinyl. They’re fine in areas with a mild climate, and are also used for commercial applications.

Fiberglass combines the higher strength and stability of aluminum with the insulating properties of wood and vinyl. Fewer options are available at this time, as fiberglass is just beginning to show up in the window market.

Combination windows are available with wood on the interior and vinyl or aluminum on the exterior, combining the look of wood with a low-maintenance exterior material. This is known as “cladding” (as in vinyl-clad or aluminum-clad).

Features to consider:

Energy efficiency. Almost any good-quality window available today incorporates two pieces of glass with a sealed airspace between then as a buffer between indoors and out. Some windows are even triple-paned. You may have the option of argon gas instead of air between the glass to further the window’s insulating abilities. Most window manufacturers also offer such options as low-E glass, which reflects heat and screens out the sun’s rays.

Design. Windows are available in shapes ranging from quarter rounds to ovals. Consider an arrangement of smaller windows instead of one large one, or vice versa.

Ease of installation. The easiest type of replacement window is a frame-within-a-frame design that can be installed in an existing frame without disturbing walls or trim work. Some are sold in kit form, complete with hardware, for standard sizes. If your original windows have divided lights or panes, look for multipane replacements or snap-in grilles that match glass dividers on the old units as closely as possible. If your windowsills are rotting or damaged, however, you’ll need to replace the old frame as well.

Ease of maintenance. Weather-resistant materials will reduce your regular maintenance; vinyl or aluminum-clad exteriors need no painting. For ease of cleaning, choose windows that tilt in or open from the side. Many double-hung windows now come with tilting sashes so both interior and exterior glass surfaces can be cleaned from inside the house.

Function. Tempered glass is required by code for certain applications, such as glass doors and some window installations with low sill height. For more extreme conditions, such as coastal environments, consider laminated impact-resistant glass designed to withstand hurricane-force winds and the impact of airborne debris.

Hardware. Some manufacturers offer improved hardware for crank-out windows such as casements and awnings — specifically, collapsible or low-profile handles that don’t interfere with blinds or other window coverings. Others offer a variety of style options for latches and locks. To be safe, ask about these and any other convenience features before the units end up in your walls. Also, try the hardware in the showroom. Does the window lock, unlock, and open easily? This test gives you a feel for the window’s usability and its overall quality as well.

Cost guidelines:
Broadly, vinyl and wood are the least expensive, fiberglass costs more, and clad windows are even more. That said, a general price range for an average size (30-inch by 48-inch) window is $100 to $200, which will be higher in urban areas.

More features?like tilting versions and higher E-ratings?increase the cost, although sometimes as the price and quality increase, more options are included. Differences in the up-front purchase price of a window may eventually be offset by other factors. Energy efficiency and a no-maintenance exterior will offset the up-front cost difference over time. Second, installation and labor costs could actually be higher for an “economy-grade” all-wood window, if you factor in charges for painting, and how much sooner you may have to replace it than a window made from more durable material.

One way to keep your window costs from rising is to avoid special orders. Try to work with standard sizes from a manufacturer, and select from the standard styles and features that your local retailer stocks.

Windows can add a lot to a home’s character. But if they’re old and worn, they can also add to your heating and cooling bills.

From Better Homes and Gardens.

In older houses, faulty windows can account for a third of the total heat loss in winter and as much as 75 percent of interior heat gain in summer. Look for the following telltale signs that a window has lost its effectiveness:

  • Stand inside your house on a windy day with a lit candle near the window’s operative edge. If the flame flickers or goes out, your weather stripping might be damaged.
  • During the winter, if a window develops ice buildup or a frosty glaze on the interior of the pane, the ventilation in your home may not be adequate. Another possibility is that your window may not be providing enough insulation value, a situation that can make your heating bills soar.
  • If you need to prop open your window with a book or a stick, the window may have lost its functionality.
  • Sit near your window. If you feel cold air coming in during the winter or warm air during the summer, your windows have little insulation value. This means you’re paying more to heat and cool your house to compensate for the exterior air entering your home.
  • Do your windows get fogged with condensation? If so, you may have a seal failure and need to replace the glazing or the entire window.

In some cases, replacing broken panes and tending to loose or missing weather stripping may buy some time. If your windows are old and ill-fitting, however, you need more than stopgaps.

Replacement window options:

Wood is the choice of most homeowners. Wood is strong, insulates well, and has natural appeal and a warm look. It needs exterior maintenance, and interior surfaces can be painted, stained, or finished any number of ways.

Vinyl windows do not need to be painted or stainedóa plus on the exterior. They offer good insulation value and strength, making them a viable alternative to wood.

Aluminum windows have a stronger frame but poorer insulation than wood or vinyl. They’re fine in areas with a mild climate, and are also used for commercial applications.

Fiberglass combines the higher strength and stability of aluminum with the insulating properties of wood and vinyl. Fewer options are available at this time, as fiberglass is just beginning to show up in the window market.

Combination windows are available with wood on the interior and vinyl or aluminum on the exterior, combining the look of wood with a low-maintenance exterior material. This is known as “cladding” (as in vinyl-clad or aluminum-clad).

Features to consider:

Energy efficiency. Almost any good-quality window available today incorporates two pieces of glass with a sealed airspace between then as a buffer between indoors and out. Some windows are even triple-paned. You may have the option of argon gas instead of air between the glass to further the window’s insulating abilities. Most window manufacturers also offer such options as low-E glass, which reflects heat and screens out the sun’s rays.

Design. Windows are available in shapes ranging from quarter rounds to ovals. Consider an arrangement of smaller windows instead of one large one, or vice versa.

Ease of installation. The easiest type of replacement window is a frame-within-a-frame design that can be installed in an existing frame without disturbing walls or trim work. Some are sold in kit form, complete with hardware, for standard sizes. If your original windows have divided lights or panes, look for multipane replacements or snap-in grilles that match glass dividers on the old units as closely as possible. If your windowsills are rotting or damaged, however, you’ll need to replace the old frame as well.

Ease of maintenance. Weather-resistant materials will reduce your regular maintenance; vinyl or aluminum-clad exteriors need no painting. For ease of cleaning, choose windows that tilt in or open from the side. Many double-hung windows now come with tilting sashes so both interior and exterior glass surfaces can be cleaned from inside the house.

Function. Tempered glass is required by code for certain applications, such as glass doors and some window installations with low sill height. For more extreme conditions, such as coastal environments, consider laminated impact-resistant glass designed to withstand hurricane-force winds and the impact of airborne debris.

Hardware. Some manufacturers offer improved hardware for crank-out windows such as casements and awnings — specifically, collapsible or low-profile handles that don’t interfere with blinds or other window coverings. Others offer a variety of style options for latches and locks. To be safe, ask about these and any other convenience features before the units end up in your walls. Also, try the hardware in the showroom. Does the window lock, unlock, and open easily? This test gives you a feel for the window’s usability and its overall quality as well.

Cost guidelines:
Broadly, vinyl and wood are the least expensive, fiberglass costs more, and clad windows are even more. That said, a general price range for an average size (30-inch by 48-inch) window is $100 to $200, which will be higher in urban areas.

More featuresólike tilting versions and higher E-ratingsóincrease the cost, although sometimes as the price and quality increase, more options are included. Differences in the up-front purchase price of a window may eventually be offset by other factors. Energy efficiency and a no-maintenance exterior will offset the up-front cost difference over time. Second, installation and labor costs could actually be higher for an “economy-grade” all-wood window, if you factor in charges for painting, and how much sooner you may have to replace it than a window made from more durable material.

One way to keep your window costs from rising is to avoid special orders. Try to work with standard sizes from a manufacturer, and select from the standard styles and features that your local retailer stocks.